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A138598
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Numbers k such that |2^(2*k-27)-27| is prime.
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0
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15, 16, 17, 23, 25, 305, 1277, 2675, 3179, 8987, 9013, 27493, 42703
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internal format)
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OFFSET
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1,1
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LINKS
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EXAMPLE
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2^(2*17-27)-27=101, 2^(2*23-27)-27=524261, 2^(2*25-27)-27=8388581, ...
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MATHEMATICA
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q=27; For[i=q, i<=q, a={}; Do[x=2^(2*n-i)-i; If[PrimeQ[x], AppendTo[a, n]], {n, 20^2}]; Print["2^(2*n-", i, ")-", i, " ", a]; i=i+2]
Select[Range[1000], PrimeQ[Abs[2^(2#-27)-27]]&] (* Harvey P. Dale, Nov 12 2015 *)
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PROG
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CROSSREFS
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KEYWORD
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more,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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